The utility model relates to a crossed inserting plate assembly tool. The assembly tool comprises a positioning plate which is provided with crossed positioning scale marks, positioning pin hanging hole frames and auxiliary tools; the auxiliary tools determine the positions on the positioning plate according to the crossed positioning scale marks. Each auxiliary tool is in the shape of L and comprises two L-shaped connected plate bodies, each plate body is provided with a plurality of positioning holes, and the connection line of the centers of the positioning holes is a straight line and perpendicular to the horizontal plane. Each positioning pin hanging hole frame comprises two opposite vertical plates and a transverse plate, the lower end face of the transverse plate is connected with the upper ends of the vertical plates, and a long hole is formed in the transverse plate. Due to the crossed inserting plate assembly tool, crossed inserting plates can be positioned and assembled; assembly of the crossed inserting plates is procedural in a spatial switching mode, positioning precision and assembling efficiency are improved, the crossed inserting plates are fixed, crossed inserting plates of a certain specification can be assembled on a large scale, and the crossed inserting plate assembly tool is high in practicability, and convenient, fast and efficient to use.